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A. I. Grabezhev Yu. L. Ronkin V. N. Puchkov G. Yu. Shardakova O. B. Azovskova A. Gerdes 《Doklady Earth Sciences》2016,466(1):92-95
The Zelenodol porphyry Cu-(Au, Mo) deposit located about 65 km SSW of the city of Chelyabinsk is confined to the western part of the West Uralian Volcanogenic Megazone. The concordant U-Pb age of zircons from ore-bearing island-arc diorite porphyryis 418.3 Â ± 2.9 Ma. 相似文献
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The peculiarities of conodont fauna redeposition of the Upper Devonian-Lower Carboniferous sediments from different structural-facial
zones of the Southern Urals (the Zilair megasynclinorium on the western slope of the Southern Urals (paleocontinental sector)
and the Magnitogorsk-Bogdanovsk graben in the central part of the Magnitogorsk megasynclinorium on the eastern slope (paleooceanic
sector)) have been studied. The regularities of conodont fauna redeposition in the flysch foredeep and riftogenous depression
(of graben) formed in the back of the volcanic arc after volcanism termination have been described. 相似文献
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U.?A.?GlasmacherEmail author W.?Bauer N.?Clauer V.?N.?Puchkov 《International Journal of Earth Sciences》2004,93(5):921-944
The eastern margin of the East European Craton (EEC) has a long lasting geological record of Precambrian age. Archaean and Proterozoic strata are exposed in the western fold-and-thrust belt of the Uralides and are known from drill cores and geophysical data below the Palaeozoic cover in the Uralides and its western foredeep. In the southern Uralides, sedimentary, metamorphic and magmatic rocks of Riphean and Vendian age occur in the Bashkirian Mega-anticlinorium (BMA) and the Beloretzk Terrane. In the eastern part of the BMA (Yamantau anticlinorium) and the Beloretzk Terrane, K-Ar ages of the <2-µm-size fraction of phyllites (potassic white mica) and slates (illite) give evidence for a complex pre-Uralian metamorphic and deformational history of the Precambrian basement at the southeastern margin of the EEC. Interpretation of the K-Ar ages considered the variation of secondary foliation and the diagenetic to metamorphic grade. In the Yamantau anticlinorium, the greenschist-facies metamorphism of the Mesoproterozoic siliciclastic rocks is of Early Neoproterozoic origin (about 970 Ma) and the S1 cleavage formation of Late Neoproterozoic (about 550 Ma). The second wide-spaced cleavage is of Uralian origin. In the central and western part of the BMA, the diagenetic to incipient metamorphic grade developed in Late Neoproterozoic time. In post-Uralian time, Proterozoic siliciclastic rocks with a cleavage of Uralian age have not been exhumed to the surface of the BMA. Late Neoproterozoic thrusts and faults within the eastern margin of the EEC are reactivated during the Uralian deformation. 相似文献
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D. E. Saveliev V. N. Puchkov S. N. Sergeev I. I. Misabirov 《Doklady Earth Sciences》2017,476(1):1058-1061
Deformed orthopyroxene grains are studied in detail in mantle peridotite. It is shown that deformation of enstatite is accompanied by its decomposition with the formation of low-temperature phases (pargasite, Fe-rich olivine) and restite represented by depleted enstatite, forsterite, and small newly formed chrome spinellide grains. The role of plastic deformation in initiation of partial melting of peridotite and in the formation new chrome spinellide grains is discussed. 相似文献
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V. N. Puchkov A. A. Krasnobaev N. D. Sergeeva S. V. Busharina S. P. Shokalsky 《Doklady Earth Sciences》2017,477(1):1295-1300
Before our studies, it was considered that the Bagrusha rhyolite–porphyry complex (BC) including veins and thin dykes occurring in the Kusa region among deposits presumably of the Satka and Avzyan Formations of the Lower and Middle Riphean, respectively. Based on the U–Pb SHRIMP and IDTIMS studies of zircons from rhyodacite—porphyry, we established the age of the BC formation of T0 = 1348.6 ± 3.2 Ma for the first time. The age obtained is inconsistent with the idea on the Paleozoic age of the BC and the geological situation shown on geological maps of the region. The age (T0 = 1348.6 ± 3.2 Ma) of rhyodacite–porphyry from the BC provides evidence for acid volcanism controlled by the Mashak (Middle Riphean) magmatic event in the region, and deposits hosting volcanic rocks of the BC cannot be younger than the base of the Middle Riphean, i.e., the Mashak Formation, which was not previously distinguished by researchers in the western part of the Kusa and Bakal–Satka regions. At the same time, it is possible that deposits hosting dykes and veins of the granite–rhyolite formation may have a Bakal (Lower Riphean) age. 相似文献